FIELD: chemistry.
SUBSTANCE: invention relates to an improved method of producing at least one product from acrolein and acrylic acid via partial oxidation of propylene, where a) purified propane is converted at the first reaction step in the presence and/or absence of molecular oxygen, at least one dehydrogenation from a group comprising homogeneous dehydrogenation, heterogeneous catalytic dehydrogenation, homogeneous oxydehydrogenation and heterogeneous catalytic oxydehydrogenation, wherein a gaseous mixture 1 is obtained, which contains unconverted propane and the formed propylene, and b) optional separation from the total amount or partial amount of the gaseous mixture 1 of a partial amount of components other than propane and propylene contained therein, e.g., hydrogen, carbon monoxide, water vapour and/or optional conversion thereof to other compounds, e.g., water and carbon dioxide, and where a gaseous mixture 1' is obtained, which contains propane and propylene, and on at least one of the following reaction steps, c) the gaseous mixture 1 or gaseous mixture 1' or a mixture from the formed gaseous mixture 1' and the remaining gaseous mixture 1 as a component of a gaseous mixture 2 are subjected to heterogeneous catalytic gas-phase partial oxidation of propylene contained in gaseous mixture 1 and/or gaseous mixture 1', wherein a gaseous mixture 3 is obtained, which contains at least one product, d) on at least one separation step, the product is separated from gaseous mixture 3 and from the remaining residual gas, at least propane is returned to the first reaction step, where purified propane is obtained from crude propane which contains ≥90 wt % propane, ≤99 wt % propane and propylene, ≥100 ppm hydrocarbons, having 2 carbon atoms, and ≥100 ppm hydrocarbons, having 4 carbon atoms, under the condition that crude propane is fed into the fractionation column and purified propane is obtained higher than the feeding point under the condition that content of hydrocarbons having 2 carbon atoms, in wt %, in terms of the contained propane, in the purified propane is more than 100% of the corresponding content in crude propane and content of hydrocarbons having 4 carbon atoms, in wt %, in terms of content of propane, in the purified propane is at most 50% of the corresponding content in crude propane.
EFFECT: method enables to cut design expenses owing to no separation of C2-hydrocarbons during distillation.
48 cl, 1 ex
